[OSM-dev] First version of long way splitter for gdalcontour output

[jamesmikedupont at googlemail.com]

yes, you can also process the images beforehand to increase the contrast.
I have been experimenting with that, using gimp , imagemagick and some of
the gdal tools.
Will be posting updates when I have more info.

Yes I think this could be put into an editor. It could even be made an
online service.

This method extracts areas of the same color, so you can see from the
radarsat that it can extract the purple areas.

the only problem is the CPU, it uses alot, gdalcontour and also produces
huge files... but we will get there some day.

mike

On Wed, Mar 10, 2010 at 10:19 PM, Graham Jones <
grahamjones139 at googlemail.com> wrote:

> James,
> This sounds interesting - to make sure I understand are you saying that you
> can use gdalcontour to process image files and extract boundaries from
> it....like forests from satellite images?   I had never thought of doing
> that - what a good idea!  I thought it would only have worked with
> monochrome images.
>
> I would really like this because I am keen to add forests to the map to
> help with outdoor navigation, but my eyes are not up to tracing them from
> satellite images.   Is this something that could be automated into an editor
> to highlight areas you might want to trace around?
>
> Regards
>
>
> Graham.
>
> On 10 March 2010 20:25, jamesmikedupont at googlemail.com <
> jamesmikedupont at googlemail.com> wrote:
>
>> I have not done any monster forests, It is just in the beginning.
>>
>> Feel free to try the program on a big file, I would be interested to know
>> how it works.
>> any bug reports will be processed asap.
>>
>> I have updated the blog post, at the bottom you will see two features i
>> extracted and the source.
>>
>> I hope to have some more results soon,
>>
>> mike
>>
>>
>> On Wed, Mar 10, 2010 at 9:21 PM, Nic Roets <nroets at gmail.com> wrote:
>>
>>> On Wed, Mar 10, 2010 at 8:54 PM, jamesmikedupont at googlemail.com
>>> <jamesmikedupont at googlemail.com> wrote:
>>> ...
>>> > Now my code works in a single pass, at least over the entire data. It
>>> builds
>>> ...
>>> > This can be optimized further. I have exploited the following
>>> optimisations
>>> ...
>>>
>>> I process the entire planet every week (+- 5 passes, +-12 counting
>>> compression and decompression). I guess I'll be able to cope if the
>>> planet grows by 40% p.a, but you make it sound if that is too slow for
>>> you.
>>>
>>> On a less "predicting the future" topic: Can you please point me to
>>> some of these monster forests or lakes you've uploaded, so that I can
>>> check that my software can handle them ? What about Potlatch ?
>>>
>>
>>
>> _______________________________________________
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>> http://lists.openstreetmap.org/listinfo/dev
>>
>>
>
>
> --
> Dr. Graham Jones
> Hartlepool, UK
> email: grahamjones139 at gmail.com
>
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